multithreadingqt4qmutex

QMutex lock in one thread and unlock in the other thread

Am I allowed to use the QMutex in the strange way: lock the QMutex in one thread, then unlock it in the other thread?

Solution

  • According to the documentation of QMutex this results in an error:

    Attempting to unlock a mutex in a different thread to the one that locked it results in an error.

    But instead of a QMutex you can use a QSemaphore as a binary semaphore, to achieve the wanted behavior.

    //create
QSemaphore semaphore(1);

//lock in thread 1
semaphore.acquire();

//unlock in thread 2
semaphore.release();